High resolution LiDAR using high frequency pulse firing

Abstract

In accordance with some embodiments, a light detection and ranging (LiDAR) scanning system includes a light source. The light source is configured to transmit a pulse of light. The LiDAR scanning system also includes a beam steering apparatus configured to steer the pulse of light in at least one of vertically and horizontally along an optical path. The beam steering apparatus is further configured to concurrently collect scattered light generated based on the light pulse illuminating an object in the optical path. The scattered light is coaxial or substantially coaxial with the optical path. The LiDAR scanning system further includes a light converging apparatus configured to direct the collected scattered light to a focal point. The LiDAR scanning system further includes a light detector, which is situated substantially at the focal point. In some embodiments, the light detector can include an array of detectors or detector elements.

What is claimed is: 
     
       1. A light detection and ranging (LiDAR) scanning system configured for detecting a physical object by transmitting a light pulse and collecting a plurality of scattered light pulses, the system comprising an electrical processing and computing device configured to perform:
 determining a plurality of candidate travel times associated with the plurality of scattered light pulses with respect to the transmitted light pulse; 
 obtaining a plurality of location profiles corresponding to the plurality of scattered light pulses detected by a light detector; 
 determining, for each of the plurality of scattered light pulses with respect to the transmitted light pulse, a travel time based on the plurality of location profiles; 
 selecting a candidate travel time based on a correlation between the plurality of candidate travel times and the travel time determined for each of the plurality of scattered light pulses; and 
 calculating, based on the candidate travel time selected, a distance of the physical object from the LiDAR scanning system. 
 
     
     
       2. The system of  claim 1 , wherein determining the plurality of candidate travel times comprises:
 determining at least one of the plurality of candidate travel times based on a time difference between a time at which the light pulse is transmitted and at least one time at which at least one of the plurality of scattered light pulses is detected. 
 
     
     
       3. The system of  claim 1 , wherein determining the plurality of candidate travel times comprises:
 determining at least one of the plurality of candidate travel times based on at least one of a geometry, an angle, a phase, or a frequency of one or more of the plurality of scattered light pulses. 
 
     
     
       4. The system of  claim 1 , wherein each of the plurality of location profiles represents a light intensity distribution associated with a corresponding scattered light pulse of the plurality of scattered light pulses. 
     
     
       5. The system of  claim 1 , wherein the light detector comprises an array of light detector elements configured to provide landing area data associated with the plurality of scattered light pulses. 
     
     
       6. The system of  claim 1 , wherein determining a travel time based on the plurality of location profiles comprises, for each of the plurality of scattered light pulses:
 determining, based on a corresponding location profile of the plurality of location profiles, a shifting distance associated with the corresponding scattered light pulse of the plurality of scattered light pulses; and 
 determining the travel time based on the shifting distance. 
 
     
     
       7. The system of  claim 6 , wherein determining the shifting distance associated with the corresponding scattered light pulse of the plurality of scattered light pulses comprises:
 determining, based on the corresponding location profile of the plurality of location profiles, a weighted center of a landing area associated with the corresponding scattered light pulse of the plurality of the scattered light pulses; and 
 determining the shifting distance based on the weighted center of the landing area. 
 
     
     
       8. The system of  claim 7 , wherein determining the weighted center of the landing area is based on a location of the landing area and a signal intensity. 
     
     
       9. The system of  claim 7 , wherein the shifting distance corresponds to a distance between the weighted center of the landing area and a location where the corresponding scattered light pulse of the plurality of scattered light pulses would have landed on the light detector had the light detector remained stationary. 
     
     
       10. The system of  claim 6 , wherein determining the travel time based on the shifting distance comprises:
 obtaining, based on the shifting distance, data related to movement of a beam steering apparatus of the LiDAR scanning system; and 
 determining the travel time based on the data related to movement of the beam steering apparatus of the LiDAR scanning system and known movement data of the beam steering apparatus. 
 
     
     
       11. The system of  claim 10 , wherein the data related to movement of the beam steering apparatus of the LiDAR scanning system comprises a shifting angle. 
     
     
       12. The system of  claim 10 , wherein the known movement data of the beam steering apparatus comprises a speed at which the beam steering apparatus moves. 
     
     
       13. The system of  claim 1 , wherein selecting the candidate travel time based on the correlation between the plurality of candidate travel times and the travel time determined for each of the plurality of scattered light pulses comprises:
 comparing, for each of the plurality of scattered light pulses, a corresponding candidate travel time of the plurality of candidate travel times and a corresponding travel time determined based on a corresponding location profile of the plurality of location profiles; and 
 selecting the candidate travel time based on a result of the comparisons for each of the plurality of scattered light pulses. 
 
     
     
       14. The system of  claim 13 , wherein selecting the candidate travel time based on the result of the comparisons for each of the plurality of scattered light pulses comprises:
 selecting the candidate travel time for which the result indicates a smallest difference between the plurality of candidate travel times and the travel time determined for each of the plurality of scattered light pulses based on the plurality of location profiles. 
 
     
     
       15. A computer-implemented method for determining a distance of a physical object based on a light pulse transmitted and a plurality of scattered light pulses collected, by a light detection and ranging (LiDAR) scanning system, the method being performed by an electrical processing and computing device and comprising:
 determining a plurality of candidate travel times associated with the plurality of scattered light pulses with respect to the transmitted light pulse; 
 obtaining a plurality of location profiles corresponding to the plurality of scattered light pulses detected by a light detector; 
 determining, for each of the plurality of scattered light pulses with respect to the transmitted light pulse, a travel time based on the plurality of location profiles; 
 selecting a candidate travel time based on a correlation between the plurality of candidate travel times and the travel time determined for each of the plurality of scattered light pulses; and 
 calculating, based on the candidate travel time selected, the distance of the physical object from the LiDAR scanning system. 
 
     
     
       16. A non-transitory computer readable medium storing one or more programs for calculating a distance of a physical object from a light detection and ranging (LiDAR) scanning system based on a transmitted light pulse and a plurality of scattered light pulses, the one or more programs comprising instructions, which when executed by an electrical processing and computing device, cause the electrical processing and computing device to:
 determine a plurality of candidate travel times associated with the plurality of scattered light pulses with respect to the transmitted light pulse; 
 obtain a plurality of location profiles corresponding to the plurality of scattered light pulses detected by a light detector; 
 determine, for each of the plurality of scattered light pulses with respect to the transmitted light pulse, a travel time based on the plurality of location profiles; 
 select a candidate travel time based on a correlation between the plurality of candidate travel times and the travel time determined for each of the plurality of scattered light pulses; and 
 calculate, based on the candidate travel time selected, the distance of the physical object from the LiDAR scanning system. 
 
     
     
       17. A light detection and ranging (LiDAR) scanning system, comprising:
 a light source configured to transmit a light pulse; 
 a beam steering apparatus configured to steer the light pulse and to collect a scattered light, wherein the scattered light is generated based on the light pulse illuminating an object in an optical path; 
 a light detector coupled to the beam steering apparatus, wherein the light detector is configured to detect the scattered light; and 
 an electrical processing and computing device electrically coupled to the light source and the light detector, the electrical processing and computing device being configured to:
 obtain a location profile of the scattered light on the light detector; and 
 based on the location profile, determine a correlation between the transmitted light pulse and the detected scattered light. 
 
 
     
     
       18. The LiDAR scanning system of  claim 17 ,
 wherein the electrical processing and computing device is further configured to determine a distance to the object. 
 
     
     
       19. The LiDAR scanning system of  claim 17 , wherein the location profile represents a light intensity distribution associated with the scattered light on a plurality of detector elements of the light detector. 
     
     
       20. The LiDAR scanning system of  claim 17 , wherein the determination of the correlation between the transmitted light pulse and the detected scattered light based on the location profile comprises configuring the electrical processing and computing device to:
 determine a center of a landing area of the scattered light based on the location profile. 
 
     
     
       21. The LiDAR scanning system of  claim 20 , wherein the electrical processing and computing device is further configured to:
 based on the center of the landing area, determine a shifting distance; and 
 based on the shifting distance, determine a shifting angle. 
 
     
     
       22. The LiDAR scanning system of  claim 21 , wherein the electrical processing and computing device is further configured to, based on the shifting angle, determine a travel time of the transmitted light pulse. 
     
     
       23. The LiDAR scanning system of  claim 22 , wherein the electrical processing and computing device is further configured to:
 determine a candidate travel time based on a time at which the light pulse is transmitted and a time at which the scattered light is detected; 
 compare the candidate travel time with the travel time determined based on the shifting angle; and 
 based on a comparison result, determine the correlation between the transmitted light pulse and the detected scattered light. 
 
     
     
       24. The LiDAR scanning system of  claim 22 , wherein the electrical processing and computing device is further configured to:
 determine a candidate travel time based on information related to the scattered light; 
 compare the candidate travel time with the travel time determined based on the shifting angle; and 
 based on a comparison result, determine the correlation between the transmitted light pulse and the detected scattered light. 
 
     
     
       25. The LiDAR scanning system of  claim 17 , wherein the electrical processing and computing device is further configured to calculate a distance to the object based on the correlation between the transmitted light pulse and the detected scattered light. 
     
     
       26. The LiDAR scanning system of  claim 17 , where the light source is configured to consecutively transmit light pulses at a time interval that is shorter than a round-trip time for a light pulse to travel between the LiDAR scanning system and a farthest-reachable object of the LiDAR scanning system. 
     
     
       27. A method for determining a distance of a physical object, the method being performed by a light detection and ranging (LiDAR) system having a beam steering apparatus, a light detector, and an electrical processing and computing device, the method comprising:
 steering, with the beam steering apparatus, a light pulse to illuminate an object in an optical path; 
 collecting, with the beam steering apparatus, a scattered light generated based on the light pulse illuminating the object in the optical path; 
 detecting, with the light detector, the scattered light; 
 obtaining a location profile of the scattered light on the light detector; and 
 based on the obtained location profile, determining a correlation between the light pulse illuminating the object in the optical path and the detected scattered light.